The Kurdish militant group TAK says it carried out Sunday’s deadly attack in the Turkish capital, Ankara.
In an online statement it said the attack, which killed 37 people, was in revenge for military operations in the mainly Kurdish south-east.
TAK, an offshoot of the banned Kurdistan Workers’ Party (PKK), had already said it was behind another bombing in Ankara last month.
Authorities in Turkey have blamed the latest attack on the PKK.
In a further development, Germany closed its embassy in Ankara and its consulate and a school in Istanbul on Thursday fearing another attack.
The foreign ministry said it had received an “unconfirmed warning”.
Sunday’s suicide car bombing took place in a busy commercial district and transport hub in the city centre.
Dozens of people wounded in the blast remain in hospital.
TAK, which stands for Kurdistan Freedom Hawks, said on its website (in Kurdish) that Sunday’s bombing was aimed at security forces and was not intended to kill civilians.
However, it warned that further civilians casualties in its attacks were inevitable.
“On the evening of March 13, a suicide attack was carried out… in the streets of the capital of the fascist Turkish republic. We claim this attack,” the group said.
Earlier this week, Turkey said one of the bombers was a woman who was a member of the PKK.
The TAK statement named her as 24-year-old Seher Doga Jiyan and included a photograph of her.
It said the attack was in revenge for Turkish military operations in the mainly Kurdish city of Cizre in south-east Turkey.
Turkey responded to Sunday’s attack by launching air strikes on Kurdish targets in northern Iraq. It said 11 people had been detained in connection with the blast.
Both the TAK and the PKK are classified as terrorist groups by Turkey and the US.
TAK has previously said it carried out the suicide bombing on a military convoy in Ankara in February that killed 28 people.